Safety mechanism for punch-presses.



W. A. D'ARCY & W. S. ROBERTSON SAFETY MECHANISM FOR PUNCH PRESS ES.

APPLICATION FILED SEPT-21. I915.

1,172,769. Patented Feb. 22, 1916.

2 SHEETSSHEET I.

n bw W. A. DARCY & W. S. ROBERTSON.

SAFETY MECHANISM FOR PUNCH PRESSES. APPLICATION FILED $55121. 1915.

Patented Feb. 22, 1916.

2 SHEETS-SHEET 2.

if l/VVE/VTORS UNITED STATES PATENT OFFICE.

WILLIAM A. DARCY AND WILLIAM S. ROBERTSON, OF ROCHESTER, YORK.

SAFETY MECHANISM FOR PUNOI-I-IRESSES.

Specification of Letters Patent.

Patented Feb. 22, 1916.

Application filed September 21, 1915. Serial No. 51,779.

To all whom it may concern:

Be it known that we, \VILLIAM A. DAnov and IVILLIAM S. ROBERTSON, citizens of the United States, and residents of the city of Rochester, in the county of Monroe and State of New York, have invented a new and useful Safety Mechanism forPunch-Presses and the like, of which the following is a specification.

This invention relates to devices for safeguarding the operators of punch presses and of like intermittently operated machinery from injury either by their own carelessness or by a failure of the clutch of the machine to operate properly.

One of the objects of the invention is to devise a simple, durable and reliable safety mechanism for punch presses which will positivelyprevent the press from accidentally repeating.

A further object of the invention is to de vise a safety mechanism of the character specified which will prevent the operation of the machine while the operators hand or arm is in the way of the ram.

Further objects and advantages of this invention will appear more fully hereinafter as the description of the construction and operation of themechanism embodying the invention progresses.

The invention consists in the parts and in the arrangements and combinations of parts, which will be fully set forth hereinafter.

In the accompanying drawing, in which is illustrated one physical embodiment of the invention and in which like parts are designated by like reference characters in the several views, Figure 1 is a front elevation of a punch press of well known construction showing a safety mechanism embodying the invention applied thereto; Fig. 2 is an enlarged detail section taken substantially on the line 22 in Fig. 1, and showing the construction of the clutch mechanism; Fig. 3 is an enlarged detail section taken substantially on the line 3-3 in Fig. 2; Fig. 4 is a side elevation of the punch press and the safety mechanism applied thereto; Fig. 5 is a detail view of a part of the safety mechanism; and Fig. 6 is a section on the line 6-6 in Fig. 3.

Referring to the accompanying drawings, the punch press to which the safety mechanism embodying the invention is applied is of ordinary construction and comprises the usual frame A, the bed plate B, the driving shaft G, the ram or plunger D, and the driving pulley E, whichalso acts as a fly wheel. The driving pulley E is journaled loosely on the driving shaft C and is held in place thereon by an end cap 5 fastened to the shaft C by a set screw 5 (see Fig. 3).

Punch presses of the type illustrated are usually provided with some form of clutch mechanism which can be actuated by the operator to connect the driving pulley E and the driving shaft C operatively together. In the particular form of clutch mechanism shown in the drawing, a collar 6 is mounted on the shaft C adjacent to the inner face of the hub of the driving pulley E; and in the inner circumferentialface of the collar 6 is formed a semi-cylindrical groove 7. A similar cylindrical groove 8 is formed in the shaft; and arranged in this groove 8 in the shaft G is a key or clutch member K comprising a cylindrical end portion 10 journaled in the end cap 5, an intermediate semicylindrical portion 11, and an inner end portion 12, substantially segmental in cross section, as shown to the best advantage in Fig. 2. In the hub of the driving pulley E are formed two semi-cylindrical grooves 9 adapted to receive the intermediate portion 11 of the key K, when said key is turned. The key K is operated by a rocker arm 13 which has a laterally projecting end portion 13 fitting into the space between the end portion 12 of the rotary key K and the wall of the groove 7 in the collar 6, and which has a hooked end 13". A compression spring 14: is interposed between the rocker arm 13 and a lug or projection 15 fixed to the collar 6. Fixed to the collar 6 are two stop pins 15 and 15 which limit the movement of the rocker arm 13. Below thecollar 6 is. a lug or projection 16 which is integral with or se cured to the frame A of the press and in which is journaled a short shaft 17 To one end of the shaft 17 is fixed a tripper arm 18, arranged to be swung in and out of the path of movement of the hooked end 13 of the rocker arm 13, and to the other end of the shaft 17 is fixed an operating arm 19.

The construction so far described forms no part of the present invention, being merely that of a punch press selected as a press suitable for showing the safety mechanism embodying the invention attached thereto. The safety mechanism vcomprises a lever 20 which has a fulcrum block 21 adjustably secured thereto by a set screw 22,

said fulcrum block being j ournaled on a suitable pin or stud 23 fixed to the frame A of the press.- On the short rear end of the lever 20 is an adjustable counterweight 24, which tends todepress that end of the lever and lift the opposite front end of said lever. A connecting block 25 is mounted on the lever 20 between two pins 26 secured therein, and said connecting block 25 has a slot or a hole therein through which the lever 20 passes, said slot being larger than said lever whereby the connecting block 25 may tilt to some extent relatively to said lever. To the upper end of the connecting block 25 is pivoted the lower end of a link 27 the upper end of which is pivoted to the operating arm 19 of the clutch mechanism. Below the lever 20 is a box-like frame 28 which is fastened by an angle bracket 29 to the frame A of the press, and which has guide slots 30 and 31 in its upper and lower end walls; and guided in the upper and lower slots 30 and 31 is-a slide 32, which has a pin 34 fixed therein near its upper end adapted to contact with the upper end wall of the frame 28 so as to limit the upward movement of said slide. Part of one edge of the slide 32 is cut away to form a shoulder 35; and fixed in said slide is a pin 36 which extends laterally beyond the planes of the front and back edges of the frame 28. The

slide 32 is connected by a rod 33 to the connecting block 25; and is pressed sidewise, that is, to the left in Figs. 4 and 5, by two compression springs 37 which are mounted on studs integral with the adjacent side wall of the frame 28, and which press against a friction plate 38 bearing against the slide 32. Also guided in the upper slot 30 and the lower slot 31 in the frame 28 is an operating plunger 39 which has part of one edge thereof cut away to form a shoulder 40 adapted to coiiperate with the shoulder 35 of the slide 32, so as to lock the plunger 39 and the slide 32 against endwise movement from each other in one direction. The plunger 39 is connected to a rod 39 which is fastened by an adjustable clamp 41 to a link 42, the lower end7f which is pivotally connected to the usual treadle 43, said treadle'43 being held in its upper position by a tension spring 44 attached thereto and to the frame A of the press.

Secured to the ram or plunger D of the press is a rearwardly extending arm 45 to which are fastened two downwardly extending cam fingers 46 which straddle the frame 28 in position to contact with the ends of the pin 36 fixed in the side 32, when the ram D is'in its lower position. A coupling sleeve 47 is adjustably secured to the front end of the lever 20 by a set screw 48; and adjustably secured to the coupling sleeve 47 by another set screw 50 is a guard supporting arm. 49 which extends transversely of the storing lever 55 extending under the lever 20, and the other end of said restoring lever fitting into the slot 57 in abracket or arm 58 rigidly secured to the ram D.

The operation of the press and the safety mechanism is as follows: When the parts are in their normal position, as shown in the drawings, the driving pulley E rotates freely on the driving shaft C; and when the operator wishes to cause the ram D to descend he presses down on the treadle 43,

which pulls the link 42, the plunger 39 and the slide 32 downwardly, since the shoulder 40 of the plunger 39 is engaged with the shoulder 35 of the slide 32. The downward movement of the slide 32 pulls down the front end of the lever 20 and forces the horizontal portion 53 of the guard down,

and also pulls the link 27 downwardly to throw the tripper arm 18 out of engagement with the rocker arm 13. In this way, the rocker arm 13 and the rotary key K are free to be moved by the spring 14, and as the driving pulley E turns and brings the next recess 9 therein opposite to the rotary key K, the spring 14 turns the key K into this recess in the driving pulley, whereby said driving pulley is rigidly connected to the driving shaft 0 and moves said shaft to cause the descent of the ram D. The parts are so proportioned that before the tripper arm 18 can be moved far enough to release the rocker arm 13, the horizontal portion 53 of the guard must be pressed to its lowermost position in which it is impossible for the operator to have his hand or arm underneath the ram D. In case the operator should have his hand in the way of the ram I D, the horizontal portion 53 of the guard would strike his hand and arrest the movement of the lever 20 and prevent suflicient movement of the link 27 and the tripper arm 18 to release the rocker arm 13 and cause the operation of the clutch mechanism. When the ram D- descends the cam fingers 46 carried by the arm 45 strike the pin 36 of the slide 32 and push said slide sidewise against the opposition of the springs 37 so as to release the shoulder 35 in said slide from the shoulder 40 of the plunger 39, whereby the lever 20 is free to be returned to its normal position by the counterweight 24, regardless of whether or not the operator st1ll holds the treadle 43 down. Shortly after the slide 32 is released from the plunger 39,

the restoring lever 55 is tilted by the descent of the ram D, and the outer end of said restoring lever engages the-under edge of the lever 2G and positively forces the front end of the lever 20 to its upper position, so as to positively move the tripper arm 18 by means of the operating arm 19 and the shaft 17 into the path of movement of the rocker arm 13. When the driving shaft C has completed its revolution the rocker arm 13 strikes the tripper arm 18 and the rotary key K is turned clear of the recess 9 in said driving pulley, thereby permitting said driving pulley to continue its rotation while the driving shaft Cremains stationary.

It should be noted that the safety mechanism shown and hereinbefore described positively prevents the press from repeating and also prevents the press from being operated while the hand or arm ef the operator is in the way of the ram of the press. In the first place, the tripper arm 18 for operating the clutch mechanism to its unclutched position is positively disconnected from the treadle 43 so that the clutch will be unclutched, re gardless of whether or not the operator holds down the treadle 43. In the next place, no reliance is placed on the counter-.

weight 24 or on a spring alone for the restoring of the tripper arm 18 to its tripping position; but on the contrary, the lever 20 and the tripper arm 18 are positively actuated by the restoring lever 55 when the ram descends and in ample time for the tripbodiment shown and described.

per arm 18 to engage the rocker arm 13. Also, the parts are arranged so that the clutch mechanism cannot be operated to its clutched position while the hand or arm of the operator is under the ram, since it is necessary for the guard to sweep across the space, which would be occupied by the ope-r ators hand or arm, before sufiicient movement can be given to the tripper arm 18 to release the rocker afrm 13.

Obviously, the safety mechanism embodying the invention may be applied to presses of other constructions than the one shown and to presses having other forms of clutch mechanisms without departing from the invention or from the particular physical em- If desired, the moving parts of the safety mechanism may be included within any suitable protecting casing or guard which will prevent tampering with the mechanism. Also, other changes may be made in the particular construction shown and described without departing from the invention, and we do not wish to be restricted to the details of the construction and arrangement of the parts shown and hereinbefore described.

What we claim as new and desire to secure by Letters Patent of the United States,

1. In a safety mechanism for punch by said shaft; clutch mechanisms for connecting said pulley to said shaft; a movable member for operating said clutch mechanism; a'treadle; a connection between said treadle and said movable member comprising disengageable lateh members; resilient means for restoring said movable member to its position for unclutching said clutch alie'clianisin; means operatively connected tosaid ram and actuated by the downward movement thereof for disengaging said latch members; and means operatively connected to said ram for positively restoring said movable member to itsposition for unclutching said clutch mechanism.

In a safety mechanism for presses and the like, in combination: a driving shaft; a driving pulley; a ram operated by said? shaft; a clutch mechanism for connecting said pulley to said shaft; a treadle; means operatively connected to said ram and actuated thereby for disconnecting said clutch mechanism and said treadle; and means operatively connected to said ram and actuated by the downward movement theijeof forapositively returning said clutch to its unclutched position.

4:. In a safety mechanism for punch presses and the like, in combination: a driving shaft ;a driving pulley; a ram operated by said shaft; clutch mechanism for connecting said shaft and said pulley; a treadle; a connection between said treadle and said clutch mechanism comprising disengageable latch members; means operated simultaneously with the downward movement of said ram fordisengaging said latch members; a movable guard arranged to sweep the space occupied by the arm or hand of 4 the operator when under said ram; and means for operatively cfonnecting said guard punch to said treadle said guard being fully operated before said clutch mechanism is actuated by said treadle to its clutching position.

5. In a safety mechanism for punch presses and the like, in combination: a driving shaft; a driving pulley; a ram operated by said shaft; clutch mechanism for connecting said pulley to said shaft; a treadle; a connection between said treadle and said clutch mechanism comprising disengaging latch members; means operatively connected to said ram and actuated by the downward movement thereof for disengaging said latch members; means operatively connected to said ram for positively restoring said clutch mechanism to its unclutched position; and a movable guard mounted to sweep the space occupied by an operators hand or arm when under said ram, said guard being operatively connected to said treadle and being fully operated thereby before said clutch mechanism is actuated by said treadle to its clutching position.-

6. In a safety mechanism for punch pressed and the like, in combination: a driving pulley; a driving shaft; clutch mechanism for connecting said pulley and said shaft; a ram actuated by said shaft; a treadle; a connection between said clutch mecha nism and said treadle comprising two disengageable latch members; a cam for disengaging said latch members; and a rigid connection between said cam and said ram.

7. In a safety mechanism for punch presses and the like, in combination: a driving pulley; a driving shaft; clutch mechanism for connecting said shaft and said pulley; a ram actuated by said shaft and said pulley; a casing; two members slidably mounted in said casing, said members having cooperating shoulders and adapted to bers, said member acted upon by said springs having a pin fixed therein; a cam arranged to engage said pin and to move said lastmentioned member out of cooperating relation with said other member; and means for operatively connecting said cam and said ram.

- 8. In a safety mechanism for punch presses and the like, in combination: a driving pulley; a driving shaft; clutch mecha- 111SI11 for connecting said driving pulley and said shaft; a ram actuated by said shaft; a treadle; a lever mounted on a fixed pivot; a connection between said lever and said clutch mechanism; a connection between said trea- 'dle and said lever comprising separable connecting members; a movable guard carried by said lever; means operated by said ram for separating said connecting members of the connection between said lever and said treadle; and means operated by said ram for positively restoring said lever to its normal position.

. WILLIAM A. DARCY.

WILLIAM S. ROBERTSON. 

